Skip to Main Content
Skip Nav Destination

At about 20 sites in the Raton basin of Colorado and New Mexico and at least 10 sites in Wyoming, Montana, and western Canada, a pair of claystone units, an iridium (Ir) abundance anomaly, and a concentration of shock-metamorphosed minerals mark the palynological Cretaceous/Tertiary (K/T) boundary. The lower unit, the K/T boundary claystone bed, is generally 1 to 2 cm thick; the upper unit, the K/T boundary impact layer is, on average, 5 mm thick. This couplet is overlain by a coal bed 1 to 16 cm thick.

The boundary claystone in the Raton basin consists mainly of kaolinite and...

You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Close Modal

or Create an Account

Close Modal
Close Modal